Project Summary/Abstract Although China and Vietnam have both ratified the FCTC, neither provides its smokers with comprehensive cost-covered smoking cessation services. Cessation by current smokers is considered by many to be the only practical way to avoid a substantial proportion of tobacco deaths worldwide before 2050. Determining how to provide effective smoking cessation services to smokers in China and Vietnam represents one of the biggest challenges in global tobacco control efforts today. Mobile health technology (mHealth) holds particular promise for China and Vietnam, two countries with rapidly increasing mobile phone usage. However, substantial adaptations of existing mHealth smoking cessation interventions are needed to address the unique sociocultural barriers to quitting smoking for Chinese and Vietnamese smokers. The long-term goals of this project are to build and strengthen the capacity to develop and disseminate evidence-based, culturally appropriate interventions for smoking cessation using mHealth approaches in China and Vietnam. The specific aims of this project are 1) to develop and examine the efficacy of a culturally-enhanced mHealth intervention to promote smoking cessation among adult male smokers in China and Vietnam; and 2) to build and strengthen sustainable capacity for rigorous research on smoking cessation intervention studies using scalable mHealth methods in China and Vietnam. This project will not only provide timely and much-needed research evidence on the effectiveness of culturally-adapted mHealth approaches in China and Vietnam, but will also build a cadre of local researchers who will be able to carry out independent mHealth smoking cessation interventions. If scaled to population level, these interventions have the potential to help millions of smokers to quit smoking in China and Vietnam.